Drilling fluids and compositions for preparing the same



United States Patent 3,214,374 DRILLING FLUIDS AND COMPQSITIONS FOR PREPARING THE SAME Thomas E. Sample, J22, Houston, Tex., assignor to Magnet Cove Barium Corporation, Houston, Tex. No Drawing. Filed Oct. 26, 1961, Ser. No. 147,739 18 Claims. (Cl. 2528.5)

This application is a continuation-impart of my copending application, Serial No. 798,598, filed March 11, 1959, now abandoned.

This invention relates to drilling fluids having improved lubricating properties and to a method of using such fluids. In one of its aspects, it relates to a composition which can be added to drilling fluids to increase the lubricity thereof.

It has been suggested that certain materials be added to a drilling mud to enhance the lubricating properties thereof. There are several objectives sought to be obtained by such addition. First, a conventional rolling cutter bit depends upon the drilling mud to lubricate the bearings of the cutters. It is not at all uncommon that a cutter bearing will fail before the cutter teeth have been worn out; and by prolonging the life of the bearings through increased lubrication, a longer bit life should be obtained. Such longer life would reduce the number of round trips required to change bits, reduce fishing jobs for lost cutters, and also reduce the danger of losing a hole during a round trip. Further, a drilling fluid having enhanced lubricating properties would reduce drill string torque, thereby reducing the likelihood of twistoffs. It would also permit the use of higher bit loadings and rotating speeds to increase the drilling rate. Moreover, it would be desirable for the lubricating properties of the drilling fluid to be such that the drill string would be oil wetted to minimize differential pressure sticking.

While other advantages might be mentioned, the above are sufficient to indicate the value of increasing the lubricating properties of drilling fluids.

In attempting to achieve the above advantages by the use of a lubricating or extreme-pressure additive to a drilling fluid, it has been found that the various known additives have been rather specific in their reaction in the drilling fluid. Thus, while a particular additive will work well in one environment, it may fail in another. For example, the additives heretofore suggested are sensitive to caustic so that they are either ineffective or of greatly reduced efliciency in fluids of elevated pH. Also, many are sensitive to oils so that their efliciency decreases as the oil content of the well fluid increases. Some of the additives have had undesired interaction with solids suspended in the drilling fluid. For example, they may cause the solids to be oil wetted. Some of the additives have poor compatibility with fluids containing substantial amounts of dissolved alkaline earth compounds such as lime base muds, wherein they tend to form curds. Foaming and poor dispersibility have been the basis for objections to still other additives. Still other additives cause the drilling fluid to fluoresce under ultraviolet light which is objectionable, since such fluorescence interferes with black light well logging operations, particularly in wild cat wells.

In general then, there has not been provided an additive which is compatible with a wide variety of drilling fluids so as to enhance the lubricating properties thereof, and it is a general object of this invention to provide such an additive.

Another object is to provide such an additive for a drilling fluid to increase the lubricity thereof despite the fact that the fluid may contain relatively large quantities of oil, may have a solids content varying over a broad ice range, may vary in pH over a wide range, may be contaminated with various salts, or may even consist essentially of water.

Another object of the invention is to provide a drilling fluid containing an additive which enhances the lubricating properties of the fluid, and yet the fluid can be used in a wide variety of treatments without destroying the lubricating properties thereof.

Another object is to provide a lubrication-enhancing additive which, though composed of one or more ingredients which in themselves are strongly fluorescent under ultraviolet light, does not impart any substantial fluorescence to the drilling fluid.

Another object is to provide a method for using such a drilling fluid containing such an additive.

In accordance with this invention, phenolic material or a mixture of phenolic materials usually produced as a by-product in the manufacture of other materials, and containing a large proportion of phenolic compounds which have open reactive ortho positions and have the para position blocked, is sulfurized to produce a sulfurbearing aromatic material. Sulfurization is conducted by treating the by-products mixture with a solution of crystalline sulfur in sulfur monochloride.

The preferred by-product materials are:

(a) a mixture of at least 10 percent each of p-propylphenol, p-methylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-prodnet in the manufacture of p-cresol by oxidation of p cumene with molecular oxygen;

(b) a mixture of p-ethyl phenol and p-isopropylphenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chloro-benzene with water and caustic soda in liquid phase;

(c) a mixture of petroleum-derived cresylic acids having as principal constituents 3,4-xylenol, trimethylphenol, C -phenols and C -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, and having a boiling point ranging from about 225 C. to about 233 C.;

(d) a mixture of trimethylphenols, C -phenols and C.;-phenols with congeneric materials produced as a byproduct from cracking petroleum oils and boiling in the range from about 234 C. to 246 C.; and

(e) a mixture of cumylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congener'ic materials produced as a by-product in the manufacture of phenol from cumene.

The sulfurization reaction apparently proceeds by addition of a chain of two or three more sulfur atoms to connect two open ortho positions of adjacent phenol rings. Presumably, when both ortho positions are unsubstituted, as is the case with a large proportion of the phenolic materials in the preferred by-product materials, more than two phenol rings may be connected through such sulfur linkages.

The phenolic starting material is sulfurized by a substantially equimolar solution of sulfur in sulfur monochloride to the extent that the resulting sulfurized base contains about three atoms of sulfur for each two molecules of phenolic material in the base.

The product may be a mixture of materials containing 2, 3, 4 or more phenol rings, having like or unlike substituents, connected through chains of sulfur atoms. It is not necessary that all sulfur in the product be in the form of 3-atom chains, some may be of greater length, and it is very likely that some 2-atom chains are present.

The phenolic starting material need not be a single compound but in the preferred by-product materials is a mixture of phenolic compounds having a substituent R in the para position effective to prevent addition of sulfur at this location and having the ortho positions open and Patented Oct. 26, 1965.

reactive toward sulfur. Thus, the phenolic starting material must have the para position blocked against addition of sulfur, must have open reactive ortho positions, and may or may not have substituents in the meta positions. Methyl, ethyl, nand iso-propyl or butyl groups are among those effective to prevent addition of sulfur in the para position. Addition of sulfur in the para position is undesirable since sulfur chains attached to both the para position and ortho position would produce a cross linked polymeric type material which has been found oil insoluble and ineffective as an extreme pressure lubricant in drilling fluids.

When mixtures of phenolic compounds, such as the by-product materials described above, are used as starting materials for the sulfurization reaction it will be seen that these by-products contain minor amounts of phenols having open reactive para positions. During sulfurization some sulfur obviously adds to these compounds, producing polymeric materials cross linked by sulfur chains in both ortho and para positions. These cross linked polymers are substantially ineffective as extreme-pressure lubricants in drilling fluids, but in minor amounts do not detract appreciably from the desired properties of the product.

It is preferred that the phenolic starting material have a molecular weight below 150, or that the average molecular weight of a mixture of phenolic materials used as starting material be below 150 so that the percentage of sulfur in the product may be easily limited to the preferred range from 24 to 28%. However heavier substituents may be present so long as the molecular weight, or average molecular weight does not exceed 250, and when such heavy starting materials are used the sulfur content of the product may decline to a minimum of 16% or so. Such low sulfur products do not have as great extreme-pressure lubricant properties as those made from the preferred starting materials.

For high efliciency of the product, it also is necessary to use crystalline sulfur dissolved in sulfur monochloride as the sulfurizing agent, as is has been found that sulfurization by sulfur monochloride alone or by sulfur alone yields inferior products. It is immaterial whether the cryastalline sulfur dissovled in sulfur monochloride to produce the sulfurizing reagent be of rhombic or monoclinic form. Amorphous sulfur is not sufficiently soluble in sulfur monochloride at temperatures below its melting point to yield products having the desired extremepressure lubricating properties in drilling fluids.

While the sulfurized product is effective in itself to enhance the lubricating properties of drilling fluids, it can be mixed with a chlorinated hydrocarbon to further increase the lubricity of the drilling fluid, particularly at low load conditions. A wool fat fraction, such as degras, also can be employed as a part of the additive mixture to increase the effectiveness of the additive in fluids containing substantial quantities of oil, such as in oil-in-water emulsion drilling fluids. Vegetable pitch also can be used with, or instead of, the wool fat fraction to increase the effectiveness of the additive in fluids containing substantial quantities of oil.

In preferred form, the above ingredients are made up to a single additive which can be added directly to the drilling fluids. This additive can be prepared in a number of manners. For example, the active ingredients can be dispersed or dissolved in a suitable hydrocarbon carrier oil, preferably with a dispersant, to provide a liquid additive. Alternatively, the ingredients can be emulsified with water, again preferably with a dispersant to provide another liquid additive. It is also contemplated that these ingredients can be made up into a dry mixture which can be added as such to the drilling fluid. Despite the preference that the additive be compounded as a single mixture, where it is composed of more than one ingredient, the ingredients thereof can be added separately to the drilling fluid if desired.

Before turning to a more detailed description of the invention, one preferred embodiment thereof will be discussed. One preferred formula for the additive is as follows:

FORMULA I Ingredients: Weight percent Sulfur-bearing aromatic material 23 Hexachlorocyclohexane 3 Common degras or vegetative pitch 4 Sodium oleyl sulfate 1 Hydrocarbon carrier oil 69 The sulfur-bearing aromatic material of Formula I may be any of the sulfurized products described above.

In a preferred method for preparing the mixture, the hydrocarbon carrier oil and the sulfur-bearing aromatic material are both preheated to about F. or somewhat higher and the latter is poured into the former with stirring. To this mixture, still at elevated temperature, is added the melted degras or vegetable pitch; and after a period of stirring, the hexachlorocyclohexane is added. The mixture is stirred for about a half hour longer or until the hexachlorocyclohexane is completely dispersed or dissolved. Finally, the sodium oleyl sulfate is added, and the completed formulation is stirred, still at about 150 F., or above, until the mixture is completely homogeneous.

The order above outlined for the addition of the various ingredients to the hydrocarbon carrier oil is not intended to be restrictive, but experience has shown it to be preferred.

When the additive of this invention is used in the form of Formula I, an amount within the range of l to 15, preferably 2 to 6, pounds per barrel of drilling fluid should be used. The minimum and optimum amounts will vary with different types of drilling fluids and can be determined by the usual routine tests. The maximum amount to be used will be dictated primarily by economics, since reasonable over-treatment does not affect the properties of the drilling fluid adversely.

Although specific materials and concentrations have been referred to in the above formula, it has been found that some latitude is possible with respect thereto, both as to the nature and the presence of some of these materials and the concentrations thereof. Further, while it has been greatly preferred to combine the ingredients as a single concentrate or additive to be added to drilling fluid as such, the ingredients can be added separately to produce a drilling fluid having enhanced lubricating properties.

SULFUR-BEARING AROMATIC MATERIALS The sulfur-bearing aromatic material of this invention preferably is prepared by sulfurizing any of the following by-product materials:

(A) A material produced by the auto-oxidation of para-cumene using molecular oxygen. In this process, both a primary hydroperoxide and a tertiary hydroperoxide are produced. The treatment of this mixture of hydroperoxides with acid catalysts results in a rearrangement which yields formaldehyde, acetone, para-cresol, para-isopropyl phenol and several other congeneric materials. The formaldehyde, acetone and para-cresol are removed as products, and a residue is left which, when distilled, yields a by-product material containing para-isopropyl phenol, para-methylacetophenone and para-isopropylbenzyl alcohol. Para-isopropyl phenol may be present in the range from about 35 to about 70 percent and paramethylacetophenone to the extent of about 10 to 401 percent. More than 10 percent of isopropylbenzyl alco-- hol also is present so that these materials are usually pres ent in an approximate ratio to ecah other of about 4:2:1.

(B) An alkylphenol mixture prepared as a by-productof the manufacture of phenol by the chlorobenzene proc ess, in which monochlorobenzene is reacted with Water:

and caustic soda in liquid phase under conditions of high temperature and high pressure to give phenol, a complex mixture of alkylphenols, diphenyl ether and sodium chloride. A fraction comprising the alkylphenols is separated from the reaction product and is stated to have the following average composition: 55 percent para-ethyl phenol, 30 percent paraisopropyl phenol, and small amounts of ortho-ethyl phenol, ortho-isopropyl phenol, ortho-phenyl phenol, ortho-sec-butyl phenol, orthocresol and phenol.

(C) A by-product material known commercially as 3,4-Xylenol Concentrate recovered from petroleum distillates such as cracked naphtha and cycle oils. The phenolic materials are removed by contacting such cracked petroleum fractions with alkali metal hydroxide in aqueous solution wherein the phenolic materials dissolve to form the corresponding sodium or potassium salts. The aqueous alkaline solution is then neutralized and the crude phenolic phase is separated therefrom by decantation. After separation, the crude cresylic acids are distilled to separate the many homologs into pure components, or narrow boiling mixtures. This distillation is usually conducted at or below atmospheric pressure using highly efficient fractionation equipment. The particular fraction utilized in the present process is designated as 3,4-Xylenol Concentrate and has a boiling range between about 225 C. and about 232 C. This fraction usually contains about 42 to 44 percent 3,4-xylenol, about 21.2 percent of trimethyl phenol and about 20 to 21 percent of C3-PhCl'l01S and C -phenols together with minor amounts of other phenolic materials including metaand para-ethyl phenols and oher xylenols.

(D) A second cut of crude cresylic acid distillate designated commercially as an alkyl phenol out also can be used as the material to be sulfurized in my process. This cut has a boiling range from about 234 to about 246 C. and contains about 90 to 95 percent C and C phenols, together with minor amounts of xylenols, metaand paraethyl phenols as well as some higher boiling materials.

(E) Crude cumyl phenol, which is a by-product of the cumene process for making phenol. In this process, cumene is oxidized to produce cumene peroxide which, when treated with an acid catalyst, produces a mixture of phenol, acetone, cumyl phenol, :acetophenone, alphamethyl styrene and other complex organic materials. After distillation of phenol and acetone from this mixture, a crude cumyl phenol material is left. A typical analysis of this material is as follows: cumyl phenol, 30 percent; unsaturated dimer, 25 percent; unknown phenolic materials boiling above cumyl phenol, 23 percent; unknown phenolic materials boiling below cumyl phenol,

16 percent; and cyclized 2,5-diphenol-1-hexane, 6 percent.

In accordance with this invention, any of the foregoing by-product materials are sulfurized with a solution of crystalline sulfur in sulfur monochloride since it has been found that either sulfur monochloride alone or elemental sulfur alone gives inferior sulfurized products.

In carrying out the sulfurization reaction, the byproduct material and the solution of sulfur in sulfur monochloride are mixed together and are reacted at a temperature in the range of about 150 to 250 F., preferably at about 200 F. which is well below the melting point of sulfur. As stated above, the sulfur and sulfur monochloride should first be formed into a separate solution; the amount of the sulfurizing solution to be employed preferably should be approximately the mol equivalent of the substituted phenolic materials present in the reaction mixture, and in any event should be sufficient that the final sulfurized product contains from about 16 to 31 percent sulfur, or preferably about 24 to 28 percent. While it is preferred that the ratio of elemental sulfur to sulfur monochloride in the solution roughly approximate equivalent quantities (i.e., 0.5 mol equivalent each of sulfur and sulfur monochloride for each mol of substituted phenol), the relative ratio can be varied somewhat. Thus, the ratio of these two sulfurizing materials to each other can be within the range of about 0.8 to 1.5 sulfur to sulfur monochloride.

The sulfurization reaction is accompanied by evolution of hydrogen chloride and usually requires from about 1.5 to 4 hours, depending upon such variables as the efliciency of agitation, the heat transfer characteristics, and the design of the reaction vessel. During the course of the reaction, the by-product material gradually darkens and thickens until at the end of the addition it is a viscous dark oil (at 200 F.). Treating and agitation should be continued until the reaction is substantially complete as evidenced by decrease in hydrogen chloride evolved.

On completion of the reaction, it is necessary that any hydrogen chloride remaining in the solution be neutralized. This can be accomplished by addition of suitable amounts of a base, such as an alkali hydroxide. However, since it is difficult to determine the amount of hydrogen chloride to be neutralized, the use of alkali hydroxide may result in either undertreatment or overtreatment. Overtreatment is undesirable since excess alkali metal hydroxide remains in the sulfurized material as a contaminant. Therefore, it is preferred that an aqueous ammonium hydroxide solution be used and usually an amount within the range of 0.1 to 0.05 mol equivalent will be sufficient. The ammonium hydroxide solution can be added to the hot reaction product and the resulting ammonium chloride drawn off. The heating period may be continued so that any excessive ammonia as well as most of the attendant water is boiled out of the mixture. Gaseous ammonia also may be employed, but ammonium hydroxide is the preferred material.

The final product is thick, reddish-black in thin films, and only slightly fluid at room temperature. It has a quite characteristic odor and is homogenous except for a slight residue of ammonium chloride resulting from the neutralization reaction. It is insoluble in water but may be permanently dispersed in most oils by heating the product in oil to a temperature of 150 to 250 F.

The amount of the sulfurized material to be used in a drilling fluid should be in the range of 0.2 to 5, preferably 0.4 to 2, pounds per barrel. While the minimum amount required to give the desired results will vary from drilling fluid to drilling fluid, depending upon the latters composition, and the formations being drilled, the maximum amount to be used seems to be dictated primarily by economics. Thus, overtreatment does not harm the mud. Therefore, in terms of obtaining desired results, it can be said that at least 0.2, preferably at least 0.4, pound per barrel of this material should be used. When the sulfurized material is combined with a carrier to form a liquid additive, it is preferred that the amount of sulfurized base be adjusted according to its sulfur content so as to yield about 6 percent to 8 percent total sulfur in the additive.

CHLORINATED HYDROCARBON While the sulfurized organic material described above can be used alone in many instances as an additive to enhance the lubricating properties of a drilling fluid, the performance of the additive is improved by the addition of a small amount of a chlorinated hydrocarbon. This is markedly true under relatively low load conditions where chlorinated hydrocarbons exhibit their best extreme-pressure lubricating properties and organic sulfur compounds are least effective. Therefore, to obtain a product giving the desired lubricating results through a Wide range of load conditions, it is preferred to add chlorinated hydrocarbon to the sulfurized product.

The chlorinated material can be selected from the class consisting of chlorinated aliphatic hydrocarbons and chlorinated cyclo-aliphatic hydrocarbons having from 5 to 21 carbon atoms per molecule. The chlorinated compound or compounds selected should have from about 40 to percent by weight of chemically bound chlorine. Especially preferred are hexachlorocyclohexane and chlorinated paraffin wax. The nature or configuration of the hydrocarbon portion of the molecule does not seem to be especially important. However, it should be large enough that the chlorinated product is not excessively volatile, as might be the case with carbon tetrachloride, for example. The prime consideration is to make available organically bound chlorine in a form that can be dispersed in the drilling fluid to remain therein during the well drilling operation. For this reason, chlorinated organic material other than chlorinated aliphatic and cyclo-aliphatic hydrocarbons may in some instances be employed. For example, some of the chlorinated aromatic series can be used as Well as certain hydrocarbons which are both chlorinated and oxygenated, as for example, chlorinated diphenyl ethers.

The amount of the chlorinated organic material to be used should be within the range of 0.02 to 1, preferably 0.05 to 0.5, pound per barrel of drilling fluid. Here again the minimum amount necessary to achieve optimum results will vary from mud to mud and can be determined by mere routine tests. Amounts in excess of the above ranges can also be used without harmful effect to the drilling fluid and hence the maximum amount is dictated primarily by economics. However, the oil solubility of the chlorinated material may impose an upper limiting factor. Accordingly, it can be said that at least 0.02, preferably 0.04, pound per barrel should be used.

OILINESS AGENT The purpose of this ingredient is primarily to improve the results obtained when the additive is employed in drilling fluids containing a substantial oil content, such as oil contents in excess of 10 to percent by volume. While the sulfurized aromatic material of this invention can be used, with or without the chlorinated hydrocarbon constituent, in drilling fluids of relatively high oil content to achieve and enhance lubricating properties thereof, better results will be obtained when an oiliness agent is added. An oiliness agent may be selected from the group derived from sheep wool grease or from the vegetable pitches. Examples falling within the sheep wool grease group are lanolin, wool wax and degras, the latter being preferred primarily due to its relatively low cost. These agents exhibit an exceptional affinity for metal and have a limited tendency toward curd formation in the presence of hard water.

As indicated above, degras is a preferred oiliness agent. This material is commercially available on the open market under this generic name.

'The vegetable pitches commonly available on the market and usable as oiliness agents in this invention are sticky, viscous, dark colored materials usually produced from cottonseed, corn or soy bean oils. In one widely used commercial process for producing vegetable pitches, a crudevegetable oil is treated with an aqueous caustic solution to convert free fatty acids and glycerides of fatty acids into soap. The complete volume of reaction products, called raw soap stock, consists of soap, oil and nonglyceride materials. The raw soap stock is treated with sulfuric acid or other mineral acids to convert soaps into free fatty acids. The resulting acid soap stock consists essentially of fatty acids, fatty acid tri-glycerides and nonglyceride materials.

The vegetable oil, acid soap stock, or a mixture of both, is passed through a high pressure continuous splitter. In the splitter, the materials are intimately mixed with Water and steam at about 500 F. and about 760 p.s.i. The water reacts with the glycerides to form free fatty acids and glycerine, which are separated. The resulting crude fatty acid fraction contains about 2 percent un saponifiables, about 4 percent glycerides and about 94 percent free fatty acids. This fraction is then fed into a continuous fractionating still where approximately 80 percent of the total material is distilled off overhead as fatty acids, while the remainder is continuously removed from the bottom of the still as stillbottom vegetable residue. The distillation usually is conducted under a pressure of about 2 to 50 mm. of mercury at a temperature up to 510 F., with a small percent of steam being injected into the base of the distillation column used. The average time the residue is subjected to these conditions is about four hours. Cottonseed oil, corn oil and soy bean oil are the principal oils treated by this process. Either a mixture of these oils or any one of them may be used as a starting material in the process just described, and accordingly the stillbottom residue may be derived from one or more of the oils. It is common practice to use a mixture of stillbottom residues of these oils as a feed material for the production of vegetable pitch, although a residue from any one or any combination of them can be fed separately to produce its corresponding pitch.

The various vegetable pitches are produced by further stripping the individual or composite still bottom residues in a pitch still under a pressure of about 2 to 5 mm. of mercury, and at a temperature of about 480 F. for approximately eight hours. This stripping is continued with removal of lighter overhead products until the stillbottom residue, which is vegetable pitch, has the desired specifications. It is quite common to produce vegetable pitches having a viscosity of 9 to 19 seconds at a temperature of 165 C. in a Zahn G-5 cup. A lighter pitch may be obtained by stopping stripping while the stillbottom products have a viscosity of about 8.5 to 10 seconds at a temperature of 125 C. in a Zahn G-S cup.

Since corn, cottonseed and soy bean oils contain relatively large proportions of unsaturated fatty acids, and these fatty acids are known to polymerize under prolonged heating, vegetable pitches produced as still residues as described above will contain 30 percent or more of polybasic fatty acid polymers.

One type of vegetable pit-ch suitable for use in this invention is readily available on the market and has the following specifications:

Unsaponifiable matter percent 15 Softening point, ball and ring C 55 Acid value 45-65 Saponifioation value 135 Iodine value 70-90 Color (B-aret) 18 Free fatty acids 1 27 Tri-glycerides and hydrides and lact-ones 1 40 1 Percent minimum.

This table is given merely as an example of one commercially available vegetable pitch usable as an oiliness agent in Formula I. In general, it may be stated that any vegetable pitch which contains at least 30 percent of polymerized polybasic fatty acids and has an acid value of at least 23 may be used as an oiliness agent. Vegetable pitches having free fatty acid content of about 26 to 28 percent are readily available on the market.

The amount of oiliness agent to be used can be an amount within the ranges described above for a chlorinated hydrocarbon. The same remarks made with respect to the amount of the latter material are applicable to the oiliness agent.

HYDROCARB ON CARRIER OIL While the sulfurized aromatic material, together with any chlorinated hydrocarbons and oiliness agents, can be separately added to a drilling fluid, or prepared as a dry mix with a suitable absorbent, they can be dispersed in a liquid medium. Such medium can comprise oil or water. The dispersion in water may be somewhat more diflicult to stabilize than a dispersion in oil and hence the latter may be preferred. The oil to be employed can comprise any suitable hydrocarbon oil having a sufliciently low viscosity that, when the other ingredients are mixed therewith, the resultant dispersion will remain 9 pourable through the range of temperature conditions existing in the field. In order to permit formation of a suitable dispersion with a minimum amount of carrier oil, it is preferred that the latter contain some aromatic, olefinic or naphthenic constituents in an amount of at least 10 percent up to as much as 80 percent, the balance being paraffinic hydrocarbons. The gravity of the oil can vary over a broad range as can its viscosity, keeping in mind that the viscosity of the oil with the other ingredients dispersed therein should be low enough that it Will remain pourable under field conditions. In this respect, the pour point of the more viscous carrier oils can be depressed by dilution, as with dieselfuel oil or aromatic naphtha, without affecting substantially the desirable properties of the additive.

One particularly useful carrier oil useful in Formula I comprises an extract of naphthenic coastal crude oil, such extract having a gravity of about14-15 API, a viscosity of about 85-165 SSU (100 F.) and a pour point of some -30 F.

The amount of carrier oilto beemployed will be that sufficient to hold the other ingredients in dispersion, and usually an amount within the range of 0.6 to 15 pounds per barrel will be sufiicient. depend upon the amount of the other ingredients dispersed therein, the characteristics of the oil and the fluidity desired. The maximum amount is notcritical and amounts in excess of the above range can readily be employed, and the only result will be that the drilling fluid will contain a higher percentage of oil.

In this connection, it has been found that the use of the additive of this invention in emulsion-muds permits a decrease in the overall amount of oil required in the emulsion to give satisfactory results. This decrease is not accounted for by the fact that the additive itself contains oil. For example, use of the additive sometimes permits an overall oil decrease to as much as One half that normally required. This not only saves oil but weighting material.

THE EMULSIFIER The purpose of this component is twofold. Primarily, the emulsifier is selected for its ability to effectively disperse, without inversion, the ingredients of the lubricating additive in the drilling fluid. Secondarily, it also aids in dispersing the active ingredients in the hydrocarbon carrier oil. An emulsifier may be particularly desirable in a low solids or a solids-free drilling fluid system or in a system containing hard water. While a number of different emulsifiers are useful, it is preferred to use an anionic emulsifier, which, of course, should be stable in The minimum amount will the presence of strong alkali, hard water, elevated tent peratures and other conditions found in the drilling of a well. Among the most satisfactory of the common anionic emulsifiers are the aliphatic alcohol sulfates, or the alkali metal salts thereof, in which the alcohol con tains from 10 to 18 carbon atoms. A specific and preferred emulsifier is the sodium salt of the sulfate of'oleyl alcohol.

The amount of emulsifier to be used can vary over considerable range. Usually, at least 0.01 poundper barrel will be found useful. Stated as a range, the amount can be from 0.01 to 0.5'pound per barrel.

While the amounts of the various ingredients which may be used in the practice of this invention have been indicated above as being within a numerical range, it will be understoodthat in certainexceptional cases it may be desirable to depart from these ranges to obtain desired results. In any event, the lubricating additive will be employed to increase the Timken load-bearing.

capacity of the fluid to at least 30 pounds.

EXAMPLE I An aromatic mixture of p-isopropylplhenol, p-methylacetophenone, and isopropylbenzyl alcohol in the approxi: mate ratio of 4:2:1 by Weight Was placed in a reactor and heated to about 200 F. For each mol equivalent of the aromatic mixture, there Was gradually added to the reactor a solution consisting of 0.5 mol equivalent of sulfur dissolved in 0.5 mol equivalent of sulfur monochloride. The addition resultedin the energetic evolution of hydrogen chloride, and required about three hours. Over the course of the addition, the aromatic mixture gradually darkened, and thickened until at the end of the addition, it Was a viscous oil (at 200 F..). Heating and agitation at 200 F. was continued for four hours. the end of this time, residual dissolved hydrogen chloride was neutralized by the additionof about 0.1 mol equivalent (based on the theoretical hydrogen chloride evolved) of concentrated ammonium hydroxide over a period of some 10 to 30 minutes. The mixture was cooked an hour longer at about 225 F., and excess ammonia as well as water was cooked out of the mixture. The final product was labeled RAP-S3.

A number of different types of waters as well as different types of muds were prepared as reflected in Table I. To some of these muds was added Formula I containing RAP-S3, in the amounts indicated in Table I, except that for Tests Nos. 25 to 28 the additives identified in the footnotes were used. After sufiicient stirring to assure a uniform dispersion ofthe additive in the mud, the Timken load capacity of each rnul sample was taken.

TABLE I Formula I Timken Load Capacity Test Fluid Additive Scar, mm. Remarks (lbsJbbL) pH Lbs. Lbs/in.

5% bentonite in water 0 8.6 5 10!) Extensive galling. d0 3. 5 8. 7 29, 850 1. 7 No oil Wetting of solids.

5% bentonite plus 1 p.p.b. each of 3. 5 12.0 100 20, 305 2. 5 D0.

NaOH and Quebracho. 5% loentonite in water and 10% diesel 0 8. 4 5 100 Extensive galling.

o1 dn 6 8.5 100 25, 375 2.0 N0 greasing out of additive.

5%Pentonite in water and 15% diesel 6 8. 7 100 26, 700 1.9 Do.

01 5% bentonite in water and 20% diesel 6 9.3 100 22,070 2.3 No oil wetting of solids and on. no greasing out of additive. Fresh water 0 7. 3 5 100 Extensive grilling. 0, 3. 5 8. 5 100' 28, 200 1.8 Smooth emulsion. Fresh water plus 6% d sel 0 7.6 5 100 Extensive galling. ..do 3. 5 8. 5 100 26, 700 1.9 Loose emulsion. Fresh water plus 15% diesel oil 6 8. 5 100 26,700 1. 9 Do.

Fresh water saturated with gypsum... 0 7. 2 5 100 Extensive gelling.

dn 3. 5 8. 2 100 25,375 2.0 No greasingsome oiling separation due to salting out efiect.

Fresh water saturated with gypsum. 6 8.2 100 25, 375 2. 0 Some oiling out due to salting plus 5% diesel oil. on

Fresh water saturated with gypsum 6 8. 2 100 28, 200 1.8 Little oiling out.

plus 15% nonionic emulsifier.

. TABLE 1C0ntinued Formula I Timken Load Capacity Test Fluid Additive Scar, mm. Remarks (lbs.lbbl.)

pH Lbs. Lbs/in.

17 Fresh water saturated with lime 12.2 O Extensive gelling. 18 .do 3.5 12. 2 80 15, 625 2. 6 No greasing. 19 Fresh Water saturated with lime plus 3. 5 12.0 100 20, 305 2. 5 D0.

. 3% diesel oil. 7

Fresh water saturated with NaCl 0 7. 4 5 100 Extensive gelling. 6 7. 4 100 25, 375 2.0 Oiling out due to salting out.

Fresh water saturated with NaGl plus 6 7. 4 100 23, 070 2. 2 Do.

10% diesel oil. 10% N aCl water saturated with 6 7. 3 100 23, 070 2. 2 Do.

gypsum. Fresh water plus 0.12% NaOH 3. 5 12.0 100 24,185 2. 1 Do. 5% bentonite in water 1 3. 5 9. -l 90 22, 850 2. 0 do 2 3. 5 8. 5 60 16, 025 1. 9 do 3 3. 5 8. 3 100 22.072 2. 3 dn 46.0 8.6 10 3,375 1.5

i dNonylphenol adducted with about 30 mols of ethylene ox e.

For Test No. the additive comprises 23 percent of sulfurized aromatic base plus 77 percent of hydrocarbon oil carrier, as described for Formula I.

For Test No. 26, the additive comprises 70 percent of hydrocarbon oil carrier, 4 percent degras, 2.7 percent hexachlorocyclohexane, 1 percent sodium oleyl sulfate and 23 percent of sulfurized aromatic base, all as per Formula I except that the aromatic base was sulfurized only with sulfur From the foregoing Table I, it can be observed that monochloride; i.e., no elemental sulfur was employed.

For Test No. 27, the additive was the same as for Test No. 26 except that the sulfurized aromatic base of Test No. 26 'was further sulfurized with an equimolar amount of elemental Zulfdr for 4 hours at 200 F. (a' total of eight hours of ea ing *For Test No. 28, the additive comprises 92 percent of hydyrocarb'on carrier, 4 percent degras, 3 percent hexachlorocyclohexane and 1 percent sodium oleyl sulfate as identified for Formula I.

the additive of this invention is compatible with drilling Degras Dull yellowfluids of many different types. The table also shows that green.

the addition of relatively large quantities of oil to the Sodium oleyl sulfate White.

fluids does not destroy the lubricating properties thereof. 30 Hydrocarbon carrier Bright bluish- Example 11 Whlte- As indicated above, the additive of this invention does 3 f seen by g fi g'g of not interfere with the non-fluorescent properties of a drill- Ei i ib 5 2:2555? g fi gz g to s mg fluld' Thls 18 61s? smalls-I Important on wlldcat wells that die overall formulation does r iot exhibit any subbiicause many geolqglts obJeq-to the presence of ultrastantial fluorescence No ex lanation can be advanced violet fluorescent 011 m a drilling mud and would find t th t p t d It afluorescent additive equally objectionable. Since this a e Presen or is unexpece resu additive contains oil and is substantially non-fluorescent, Example III it is possible to substitute the additive completelyior 40 Several by product materials containing large propop 5 and P 'avold havmg to use premium tions of phenolic substances having the para position Pnce uorescen 01 blocked but having open, reactive ortho positions were To demonstrate the above properties a Series of Fests sulfurized as described under Example I above. The for fluorescence W t made under an ultravlohaft.hght sulfurized materials were neutralized with ammonium The preferred additive of Formula I above exhibited a hydroxide and excess ammonia and Water were boiled very faint yellow (almost imperceptible) fluorescence. out of thesulfurized product h .Such addmve was dlspgsed 5 percent of ham A number of different types of mud were prepared as tonne Water at a concentratl-on 6 pounds per barrel shown in the following table. Additives having substanthe resultmg. fluorescence the fluid was a trace yellqw tially the proportions shown in Formula I were prepared .(almost 1101.16) A l P of percent of P q from each of the sulfurized materials. The quantities of m water wlthout l has a shghfly brownish vlolet additive added to various types of mud are shown in the color under ultraviolet light. It Wlll thus be seen that table below and each of these muds were tested for ex i the addltlve fins 'l 9 not Impart fluores' treme pressure lubricating properties with the results cence to a drilling fluid, but instead may tend to suppress Shown in Table H any natural fluorescence the fluid may otherwise have. The vegetable l'mch used Test No 20 was a Thls fact 15 .Pamcularly surpnmg vlew of the l q mercial product sold under the specifications given above, cent properties of some of the mgredients of the addltives. and the various bshmoduct material listed as These ti Set out below C, D and E under the column headed .Phenolic. Component: Fluorescence Material were the phenolic by-product materials de- Sulfur-bearing aromatic material Black. scribed in the paragraphs labeled (a), (b), (c), (d) Hexachlorocyclohexane None. and (e) above.

- TABLE 11 Tim n Power (K.W.) Test Phenolic Type Fluid Additive Percent Load Scar Remarks Material (lbs./bbl.) Oil Cafipcity (mm.) M

s. ax. Min.

1 5% bentonite in water 0 0 5 Extensive galling 2 A- 3.5 0 100 1.2 Narrow scar; good addi- 1.3 1.0

tive; highly polished. 3 A do 6 15 100 1.5 Gooclli adiliitive; highly L4 1,1

0 S 4 A Unweightgd high solids lab. 6 0 30 E tensise galllngm; 1.5

I8 are 5 A d l2 0 60 1.7 Fair additive; polished 1,3 Q8 6 A Weightediigh solids lab. 6 0 3.0 Slight additive 09 Q7 prepare TABLE IICo11tinued Tirnken Power (K.W.) Test Phenolic Type Fluid Additive Percent Load Scar Remarks Material (lbsJbbL) Oil Capacity (man) 7 (lbs.) Max. Min.

6 5 30 Extensive galling 12 100 2. 3 Good additive; polished 0. 3. 5 0 100 1. 7 Good additive; striation 1. 4 0.7 6 15 70 2. 5 Good additive; minor 0.92 0. 9

striations. Unweighiiied high solids lab. 6 0 100 2. 5 Slightly polished 1.2 0.9

prepare d0 6 5 100 1.8 Soft additive; polished 1.1 0.9 Weighted high solids lab. 6 0 100 2.0 Good additive; polished 0.9 0.5

prepared. do 6 5 50 2.1 -..do 0.8 0.5 12 0 100 2. 7 Fair additive; polished 1.0 0. 6 12 5 100 3. 2 Fair additive; no striations 1. 1 0.9 3. 5 0 100 1. 5 Good additive; minor 1. 1 0.7

striations. d0 6 15 100 1.7 1.1 1.1 Unweighted high solids lab. 6 0 100 1. 7 Good additive; highly 0.7 0.5

prepared. polished. .do 6 O 100 1.8 Good additive; polished".-. 0.9 0.5 Weighted high solids lab. 6 0 100 1. 7 d0 0.8 0. 5

prepared. do 3. 5 5 100 2. 4 Good additive; minor 1.1 0.9

. striations. 5% bentonite in water 3. 5 0 100 1. 9 do 1. 4 0. 9 0 6 100 2. 3 Small amount additive; 1. 2 1. 1

polished. Unweighted high solids lab. 6 l) 80 1.5 Fair additive; polished 0. 9 0. 5

prepared. d0 6 5 1.6 dO 0.6 0.5 do 12 0 100 2.0 Good additive; slight polish. 1.1 0.8

Weighted high solids lab. 6 0 30 Extensive galling.

prepared. do 6 5 30 do-- 12 0 100 2. 5 Good additive; polished 1.1 0. 7 12 5 100 2. 5 Excelllelilnt additive; slight 1. 4 1. 2 po 15 5% bentonite in water 3. 5 0 100 1. 4 Fair additive; polished 1.1 0.7 do 6 15 100 1.4 d0. 0.9 0.8 Unweighted high solids lab. 6 0 100 1. 7 Good additive; polished 1.0 0. 6

prepared. do 6 5 100 1. 9 Good additive; minor .0 0.7

striations. Weighted high solids lab. 6 0 100 2.0 Little additive; minor 0.9 0. 6

prepared. striations. 87 D do 6 5 100 2. 7 Good additive; many 1. 0 0.6

striations. 38 D do 12 0 100 2. 3 Good additive; minor 1.1 0.8

striations. 39 D do 12 5 8O 2. 1 Little additive; polished- 1.0 0. 9

This additive contained a cottonseed pitch as an oiliness agent instead of degras.

The unweighted high-solids fluids in the above table were prepared by use of a mixture of clays containing 25 parts by weight sodium montmorillonite, 50 parts by weight calcium sub-bentonite and 25 parts by weight grundite. Approximately 85 pounds per barrel of this clay mixture were added to water, and the resulting slurry was diluted approximately 60 percent with Water to give a suspension having the following properties:

The weighted mud was prepared by adding barite to the high-solids mud in quantity sufiicient to give a weight of 11.9 pounds per gallon and was thinned by addition of about 0.1 pound per barrel of sodium tetraphosphate. This weighted mud had the following properties:

A.V. P.V. 14 Y.P. 42 Initial gel 38 10-minute gel 47 API fluid loss 14.6 Percent solids 42.0 Weight lbs./gal 11.9

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the composition and process.

It will be understood that certain features and subcom-' binations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1s:

1. A drilling fluid comprising a mixture of water and an additive imparting lubricating properties thereto, said additive being present in a minor amount sufficient to increase the Timkin load-bearing capacity of the fluid to at least 30 pounds and including from 0.2 to 5.0 pounds per barrel of a sulfurized aromatic base, said base being a material selected from the group consisting of (a) a mixture of at least 10 percent each of p-propyl phenol, pmethylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-product in the manufacture of p-cresol by oxidation of p-cumene with molecular oxygen; (b) a mixture of p-ethyl phenol and p-isopropyl phenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chlorobenzene with water and caustic soda in liquid phase; (0) a mixture of petroleum-derived cresylic acids having as principal constituents 3,4-xylenol, trimethylphenol, C.;-phenols and (l -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, having a boiling range from about 225 to about 233 C.; (d) a mixture of trimethylphenols, C phenols and C.;-phenols With congeneric materials produced as a by-product from cracking petroleum oils, boiling in the range from about 234 C. to 246 C.; and (e) a mixture of cumylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congeneric materials produced as a byproduct in the manufacture of phenol from cumene, said base having been sulfurized at a temperature in the range from 150 to 250 F. by a solution of sulfur in sulfur monochloride to such extent that the sulfurized base contains from 16 to 31 percent sulfur.

2. The drilling fluid of claim 1 wherein the sulfurized aromatic base is a mixture of at least 10 percent each of p-propyl phenol, p-methylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-product in the manufacture of p-cresol by oxidation of p-cumene with molecular oxygen, sulfurized at about 200 F. with a solution of crystalline sulfur in sulfur monochloride substantially to the extent that it contains three atoms of sulfur for each two molecules of phenolic material contained therein.

3. The drilling fluid of claim 1 wherein the sulfurized aromatic base is a mixture of p-ethyl phenol and p-isopropyl phenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chlorobenzene with water and caustic soda in liquid phase, sulfurized at about 200 F. with a solution of crystalline sulfur in sulfur monochloride substantially to the extent that three atoms of sulfur are present for each two molecules of phenolic material contained therein.

4. The drilling fluid of claim 1 wherein the sulfurized aromatic base is a mixture of petroleum-derived cresylic acids having as principal constituents 3,4-xylenol, trimethylphenol, C.,-phenols and C -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, having a boiling range from about 225 C. to about 233 C., sulfurized at about 200 F. with a solution of crystalline sulfur in sulfur monochloride substantially to the extent that three atoms of sulfur are present for each two molecules of phenolic material contained in said mixture.

5. The drilling fluid of claim 1 wherein the sulfurized aromatic base is a mixture of trimethylphenols, C -phenols and C -phenols with congeneric materials produced as a by-product from cracking petroleum oils, boiling in the rangefrom about 234 C. to 246 C., sulfurized at about 200 F. with a solution of crystalline sulfur in sulfur monochloride substantially to the extent that the sulfurized base contains three atoms of sulfur for each two molecules of phenolic material contained in said mixture.

6. The drilling fluid of claim 1 wherein the sulfurized aromatic base is a mixture of cumylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congeneric materials produced as a by-product in the manufacture of phenol from cumene, sulfurized at about 200 F. with a solution of crystalline sulfur in sulfur monochloride substantially to the extent that the sulfurized base contains three atoms of sulfur for each two molecules of phenolic material contained in said mixture.

7. The drilling fluid of claim 1 containing clay solids, and wherein the additive includes 0.02 to 1.0 pound per barrel of a material selected from the group consisting of chlorinated aliphatic and cyclo-aliphatic hydrocarbons having from 5 to 21 carbon atoms per molecule and containing about 40 to 80 percent by weight of bound chlorine, about 0.2 to 1.0 pound per barrel of a material selected from the group consisting of vegetable pitch and Degras.

8. The drilling fluid of claim 7 containing at least one pound per barrel of alkali hydroxide.

9. The drilling fluid of claim 7 wherein the fluid also contains suflicient oil that the total oil content of the fluid is at least 10 percent by volume and the fluid is an oil-in-water emulsion.

10. A drilling fluid comprising water, clay solids, and from 0.2 to 5.0 pounds per barrel of a sulfurized phenolic material made by reacting at least one para alkyl phenol having unsubstituted, reactive ortho positions and a molecular weight below 250 with a substantially equimolar solu-' tion of sulfur in sulfur monochloride at a temperature in the range from to 250 F. in such proportion that the resulting sulfurized phenolic material contains from 16 to 31 percent sulfur.

11. An additive for imparting lubricating characteristics to a drilling fluid comprising a sulfurized organic base, said base being a material selected from the group consisting of (a) a mixture of at least 10 percent each of p-propyl phenol, p-methylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-product in the manufacture of p-cresol by oxidation of p-cumene with a molecular oxygen; (b) a mixture of p-ethyl phenol and p-isopropyl phenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chlorobenzene with water and caustic soda in liquid phase; (c) a mixture of petroleumd'erived cresylic acids having as principal constituents 3,4- xylenol, trimethylphenol, C.,-phenols and C -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, having a boiling range from about 225 C. to about 233 C.; (d) a mixture of trimethylphenols, C -phenols and C.,-phenols with congeneric materials produced as a by-product from cracking petroleum oils, boiling in the range from about 234 C. to 246 C.; and (e) a mixture of cumylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congeneric materials produced as a b-y-product in the manufacture of phenol from cumene, sulfurized at a temperature in the range from about 150 to 250 F. by a substantially equimolar solution of sulfur in sulfur monochloride to the extent that the sulfurized base contains about three atoms of sulfur for each two molecules of phenolic material in the base.

12. The additive of claim 11 wherein the organic base is a mixture of at least 10 percent each of p-propyl phenol, p-methylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-product in the manufacture of p-cresol by oxidation of p-cumene with molecular oxygen.

13. The additive of claim 11 wherein the organic base is a mixture of p-ethyl phenol and p-isopropyl phenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chlorobenzene with water and caustic soda in liquid phase.

14. The additive of claim 11 wherein the organic base is a mixture of petroleum-derived cresylic acids having as principal constituents 3,4-xylenol, trimethylphenol, C phenols and C -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, having a boiling range from about 225 C. to about 233 C.

15. The additive of claim 11 wherein the organic base is a mixture of trimethylphenols, C -phenols and C phenols with congeneric materials produced as a by-prod: not from cracking petroleum oils, boiling in the range from about 234 C. to 246 C.

16. The additive of claim 11 wherein the organic base is a mixture of cumylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congeneric materials produced as a by-product in the manufacture of phenol from cumene.

17. An additive for imparting lubricating characteristics to a drilling fluid comprising a sulfurized organic base, said base being a material selected from the group consisting of (a) a mixture of at least 10 percent each of p-propyl phenol, p-methylacetophenone and p-isopropyl benzyl alcohol with congeneric materials produced as a by-product in the manufacture of p-cresol by oxidation of p-cumene with molecular oxygen; (b) a mixture of pethyl phenol and p-isopropyl phenol with congeneric materials produced as a by-product in the manufacture of phenol by reaction of chlorobenzene with water and caustic soda in liquid phase; a mixture of petroleumderived cresylic acids having as principal constituents 3,4- xylenol, trirnethylphenol, C -phenols and C -phenols with congeneric materials produced as a by-product from the cracking of petroleum oils, having a boiling range from about 225 C. to about 233 C.; (d) a mixture of trimethylphenols, C -phenols and C -phenols with congeneric materials produced as a by-product from cracking petroleum oils, boiling in the range from about 234 C. to 246 C.; and (e) a mixture of curnylphenol, unsaturated dimer thereof, cyclized 2,5-diphenol hexene with congeneric materials produced as a by-product in the manufacture of phenol from cumene, sulfurized at a temperature in the range from about 150 to 250 F. by a sub stantially equimolar solution of sulfur in sulfur monochloride to the extent that the sulfurized base contains about three atoms of sulfur for each two molecules of phenolic material in said base; a compound selected from the group consisting of chlorinated aliphatic and cycloaliphatic hydrocarbons having from 5 to 21 carbon atoms per molecule and containing from 40 to 80 percent bound chlorine, in amount within the range of to 35 percent of the weight of sulfurized aromatic base; and a hydrocarbon carrier oil in quantity to suspend the sulfurized aromatic base and chlorinated hydrocarbons.

18. The additive of claim 17 containing approximately 23 weight percent of said sulfurized aromatic base, about 3 percent of hexachlorocyclohexane, about 4 percent of a material selected from the group consisting of vegetable pitch and derivatives of sheep wool grease and about 1 percent of sodium oleyl sulfate.

References Cited by the Examiner UNITED STATES PATENTS 1,778,447 10/30 Burkhardt 25252 2,139,321 12/38 Mikeska et al 260137 2,253,228 8/41 Cantrell et a1. 252482 2,555,794 6/51 Henkes et a1. 2528.5 2,562,800 7/51 Leiber 25248.2 2,773,030 12/56 Tailleur 252 3,027,324 3/62 Rosenberg 2528.5 3,047,493 7/62 Rosenberg 25285 OTHER REFERENCES JULIUS GREENWALD, Primary Examiner. 

1. A DRILLING FLUID COMPRISING A MIXTURE OF WATER AND AN ADDITIVE IMPARTING LUBRICATING PROPERTIES THERETO, SAID ADDITIVE BEING PRESENT IN A MINOR AMOUNT SUFFICIENT TO INCREASE THE TIMKIN LOAD-BEARING CAPACITY OF THE FLUID TO AT LEAST 30 POUNDS AND INCLUFING FROM 0.2 TO 5.0 POUNDS PER BARREL OF A SULFURIZED AROMATIC BASE, SAID BASE BEING A MATERIAL SELECTED FROM THE GROUP CONSISTING OF (A) A MIXTURE OF AT LEAST 10 PERCENT EACH OF P-PROPYL PHENOL, PMETHYLACETOPHENONE AND P-ISOPROPYL BENZYL ALCOHOL WITH CONGENERIC MATERIALS PRODUCED AS A BY-PRODUCT IN THE MANUFACTURE OF P-CRESOL BY OXIDATION OF P-CUMENE WITH MOLECULAR OXYGEN; (B) A MIXTURE OF P-ETHYL PHENOL AND P-ISOPROPYL PHENOL WITH CONGENERIC MATERIALS PRODUCED AS A BY-PRODUCT IN THE MANUFACTURE OF PHENOL BY REACTION OF CHLOROBENZENE WITH WATER AND CAUSTIC SODA IN LIQUID PHASE; (C) A MIXTURE OF PETROLEUM-DERIVED CRESYLIC ACIDS HAVING AS PRINCIPAL CONSTITUENTS 3,4-XYLENOL, TRIMETHYLPHENOL, C4-PHENOLS AND C3-PHENOLS WITH CONGENERIC MATERIALS PRODUCED AS A BY-PRODUCT FROM THE CRACKING OF PETROLEUM OILS, HAVING A BOILING RANGE FROM ABOUT 225* TO ABOUT 233*C.; (D) A MIXTURE OF TRIMETHYLPHENOLS, C3PHENOLS AND C4-PHENOLS WITH CONGENERIC MATERIALS PRODUCED AS A BY-PRODUCT FROM CRACKING PETROLEUM OILS, BOILING IN THE RANGE FROM ABOUT 234*C. TO 246*C.; (E) A MIXTURE OF CUMYLPHENOL, UNSATURATED DIMER THEREOF, CYCLIZED 2,5-DIPHENOL HEXENE WITH CONGENERIC MATERIALS PRODUCED AS A BY-PRODUCT IN THE MANUFACTURE OF PHENOL FROM CUMENE, SAID BASE HAVING BEEN SULFURIZED AT A TEMPERATURE IN THE RANGE FROM 150* TO 250*F. BY A SOLUTION OF SULFUR IN SULFUR MONOCHLORIDE TO SUCH EXTENT THAT THE SULFURIZED BASE CONTAINS FROM 16 TO 31 PERCENT SULFUR. 